I'm trying to figure out a way to create a zero-width, zero-height image which would conform to the standard of whichever format works.
I've already tried the Windows Bitmap (BMP) format (54-byte header only file), but it appears that image readers will not accept it.
Theoretical 0x0-BMP byte string:
424D360000000000000036000000280000000000000000000000010020000000000000000000C40E0000C40E00000000000000000000
Which format would support this, and which tools can I use to create it? Even a programming solution would suffice (e.g. a C# System.Drawing script).
Image readers will tend not to accept a width of less than 1 or a height of less than 1. Hence we need to stay with 1x1 as the minimum that can be practically used, even if 0x0 is allowed by the specs of some image formats. A 67-byte PNG is detailed at http://garethrees.org/2007/11/14/pngcrush/ perhaps the smallest possible. A transparent one can be done in 67 bytes also.